Superior, Montana climate: Normal weather by month, frost dates and records
Superior's normal year runs from 22°F December nights to 89°F July afternoons, with 16.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.7°C, December lows of −6°C, July highs of 31°C, 417 mm of precipitation a year.
- NOAA stationSuperior
- Station IDUSW00024159
- Location47.19°N 114.89°W
- Elevation2,710 ft (826 m)
- Population940
On October 22, the normal high in Superior is 57°F and the normal low 32°F, and the chance of measurable rain or snow is 32%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Superior.
- Jan 36° 22°
- Feb 42° 22°
- Mar 53° 27°
- Apr 61° 32°
- May 71° 40°
- Jun 78° 46°
- Jul 89° 51°
- Aug 88° 49°
- Sep 77° 42°
- Oct 61° 34°
- Nov 43° 27°
- Dec 34° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Superior each month?
July is the warmest month, with normal highs of 89°F; December the coldest, with normal lows of 22°F. The most precipitation falls in June (2.03 in), the least in July (0.93 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 36°F | 22°F | 28.6°F | 1.19 | 10 | <1 | 28 | 8 h 50 min |
| February | 42°F | 22°F | 32.1°F | 1.29 | 9 | <1 | 25 | 10 h 20 min |
| March | 53°F | 27°F | 40.0°F | 1.11 | 10 | <1 | 23 | 11 h 50 min |
| April | 61°F | 32°F | 46.5°F | 1.36 | 11 | <1 | 15 | 13 h 30 min |
| May | 71°F | 40°F | 55.3°F | 1.80 | 10 | 1 | 4 | 15 h |
| June | 78°F | 46°F | 61.6°F | 2.03 | 10 | 4 | <1 | 15 h 50 min |
| July | 89°F | 51°F | 69.6°F | 0.93 | 6 | 16 | <1 | 15 h 30 min |
| August | 88°F | 49°F | 68.8°F | 1.05 | 5 | 15 | <1 | 14 h 20 min |
| September | 77°F | 42°F | 59.5°F | 0.99 | 7 | 3 | 3 | 12 h 40 min |
| October | 61°F | 34°F | 47.2°F | 1.34 | 9 | <1 | 13 | 11 h |
| November | 43°F | 27°F | 34.9°F | 1.95 | 12 | <1 | 22 | 9 h 20 min |
| December | 34°F | 22°F | 27.8°F | 1.38 | 11 | <1 | 28 | 8 h 30 min |
| Year (annual) | 61°F | 34°F | 47.7°F | 16.42 | 111 | 38 | 161 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 2°C | −6°C | −1.9°C | 30 mm |
| February | 6°C | −5°C | 0.1°C | 33 mm |
| March | 11°C | −3°C | 4.4°C | 28 mm |
| April | 16°C | 0°C | 8.1°C | 35 mm |
| May | 22°C | 4°C | 12.9°C | 46 mm |
| June | 25°C | 8°C | 16.4°C | 52 mm |
| July | 31°C | 10°C | 20.9°C | 24 mm |
| August | 31°C | 10°C | 20.4°C | 27 mm |
| September | 25°C | 5°C | 15.3°C | 25 mm |
| October | 16°C | 1°C | 8.4°C | 34 mm |
| November | 6°C | −3°C | 1.6°C | 50 mm |
| December | 1°C | −6°C | −2.3°C | 35 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Alberton (23 miles away), gets 49 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024159; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Superior?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (7).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024159.
When is the last frost in Superior?
In Superior, the last spring frost (32°F) comes after May 17 in half of years and after June 8 in one year in ten; the first autumn frost comes before September 23 in half of years and before September 6 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 171 year in 10 after June 8; 9 in 10 after May 1
- First autumn frost, half of years before
- September 231 year in 10 before September 6; 9 in 10 before October 7
NOAA puts the median frost-free season at 125 days, and the season without a hard freeze (28°F) at 157 days.
A hard freeze (28°F) comes after May 1 in half of springs and before October 6 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Superior in zone 6a in ZIP code 59872, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Superior's NOAA station is in zone 6a: the coldest night of a typical year reaches −6°F (18 complete years).
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00024159; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Superior?
In a normal year in Superior, 38 days a year reach 90°F (3 of them 100°F or more), 161 nights fall to 32°F or colder and 111 days bring measurable precipitation.
- Days at 90°F or more
- 38a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 161a normal year
- Days that stay below freezing
- 27high of 32°F or less
- Days with 0.01 inch of precipitation
- 111a normal year
The highest temperature in this station's record (since 1914) is 108°F, on July 15, 1935; the lowest is −36°F, on January 20, 1937.
The wettest calendar year on that record is 1927, with 23.47 in; the snowiest season is 1950–51, with 87.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024159; records: ACIS (NOAA Regional Climate Centers), station USW00024159. Records use complete months only; a month missing more than three days is left out.
How sunny is Superior?
Over a year 71% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Superior, 3.7 kWh per square metre a day. July is the sunniest month (87%) and December the cloudiest (51%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 54% | 1.1 |
| February | 60% | 2.0 |
| March | 62% | 3.2 |
| April | 66% | 4.5 |
| May | 69% | 5.6 |
| June | 71% | 6.2 |
| July | 87% | 7.3 |
| August | 84% | 6.0 |
| September | 77% | 4.2 |
| October | 66% | 2.5 |
| November | 54% | 1.3 |
| December | 51% | 0.9 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Superior need?
A normal year in Superior brings 6,694 heating degree days, 25% more than the median U.S. place (5,373), and 400 cooling degree days, 56% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,129 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,127 | 0 |
| February | 920 | 0 |
| March | 775 | 0 |
| April | 557 | 0 |
| May | 309 | 8 |
| June | 143 | 41 |
| July | 32 | 173 |
| August | 34 | 151 |
| September | 190 | 26 |
| October | 552 | 0 |
| November | 903 | 0 |
| December | 1,153 | 0 |
| Year (annual) | 6,694 | 400 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024159. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Superior's climate compare?
Superior is warmer than 134 of the other 140 places with their own NOAA record in Montana, and wetter than 97. Across the 7,247 U.S. stations with normals, its annual mean of 47.7°F is warmer than 31%.
In the Köppen classification computed from these normals, Superior is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Superior share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Riverbend, MT505 people · 4 mi SE
- Paradise, MT66 people · 14 mi N
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Superior's climate
What is the coldest month in Superior?
December, with a normal high of 34°F and a normal low of 22°F. The warmest is July (89°F by day, 51°F at night).
Does it snow in Superior?
Yes. NOAA publishes no 1991-2020 snowfall normal for Superior's NOAA station; the nearest record that keeps one, Alberton (23 miles away), records 49 inches of snow in a normal year.
What is the rainiest month in Superior?
June, with 2.03 in of precipitation in a normal year; the driest is July with 0.93 in.
What plant hardiness zone is Superior in?
The USDA's 2023 map puts Superior in zone 6a in ZIP code 59872, the nearest ZIP area. By the same method at Superior's NOAA station, the coldest night of a typical year reaches −6°F (18 years, 1991-2020): zone 6a.
How late can frost come in Superior?
In half of years the last 32°F night comes after May 17; in one year in ten it comes after June 8. Waiting until June 8 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- St. Regis, MT12 miles from this station, 46.2°F a year
- Alberton, MT24 miles from this station, 45.4°F a year
- Haugan, MT29 miles from this station, 42.2°F a year
- Thompson Falls, MT35 miles from this station, 47.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made